In semiconductor device fabrication, after the devices are created, for example, transistors are formed in front end of the line (FEOL), and are interconnected in back end of the line (BEOL). Electrical connections to the devices, also referred to as “metallization”, are in the back end of the line (BEOL).
In the current integration scheme for metal one (M1) Trench First Metal Hard Mask (TFMHM), the use of wet chemistries to remove titanium nitride (TiN) hard mask layer will also attack the exposed metal material, for example, titanium (Ti), titanium nitride (TiN) and/or tungsten (W), in the contact module below M1, resulting in the attack and the loss of the exposed metal material.
Therefore, it may be desirable to develop methods of using an alternative hard mask to replace TiN, so that the hard mask may be removed in the M1 TFMHM module without damaging the exposed metal material in the contact module.